Ultrasonic probe and ultrasonic instrument

ABSTRACT

The ultrasonic probe for a shoulder joint includes a curved extending section curved to a probe main body toward a first intersecting direction intersecting a longitudinal axis. The curved extending section includes a first curved outer surface facing the first intersecting direction, a second curved outer surface facing a second intersecting direction opposite of the first intersecting direction, a third curved outer surface facing a first width direction perpendicular to the first and second intersecting directions, and a fourth curved outer surface facing a second width direction opposite of the first width direction. A cutting surface on the second curved outer surface is different from a cutting surface on each of the third curved outer surface and the fourth curved outer surface in extending pattern of the grooves.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a Continuation application of PCT Application No.PCT/JP2015/076187, filed Sep. 15, 2015 and based upon and claiming thebenefit of priority from prior Japanese Patent Applications No.2015-001840, filed Jan. 7, 2015, the entire contents of which areincorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an ultrasonic probe to perform cuttingof, for example, a hard bone tissue and a cartilage tissue by ultrasonicvibration.

2. Description of the Related Art

In Jpn. Pat. Appln. KOKAI Publication No. 2005-152098, there isdisclosed an ultrasonic treatment device including an ultrasonic probe(an ultrasonic horn). In this ultrasonic treatment device, an ultrasonicvibration generated in a vibration generating section (an ultrasonicvibration mechanism) is transmitted from a proximal side toward a distalside in the ultrasonic probe. In a distal portion of the ultrasonicprobe, a scalpel portion is formed as a treating surface. In the scalpelportion, an outer surface of the ultrasonic probe is formed in an unevenstate. The ultrasonic vibration is transmitted to the scalpel portion ina state where the scalpel portion is in contact with a treated target,whereby the treated target (e.g., a bone or another hard tissue) is cut.

BRIEF SUMMARY OF THE INVENTION

According to one aspect of the invention, an ultrasonic probe used in ashoulder joint, the ultrasonic probe being configured to transmit anultrasonic vibration so as to treat the shoulder joint by use of theultrasonic vibration, the ultrasonic probe including: a probe main bodysection which is extended along a longitudinal axis, and which isconfigured to transmit the ultrasonic vibration from a proximal sidetoward a distal side; a curved extending section which is provided onthe distal side with respect to the probe main body section, and whichis extended in a state of curving relative to the probe main bodysection toward a first intersecting direction side in a case where acertain direction intersecting the longitudinal axis is defined as thefirst intersecting direction; a first curved outer surface which facesthe first intersecting direction side in the curved extending section; asecond curved outer surface which faces a second intersecting directionside in the curved extending section in a case where an oppositedirection of the first intersecting direction is defined as the secondintersecting direction; a third curved outer surface which faces a firstwidth direction side in the curved extending section in a case where twodirections which intersect the longitudinal axis and are perpendicularto the first intersecting direction and the second intersectingdirection are defined as a first width direction and a second widthdirection; a fourth curved outer surface which faces a second widthdirection side in the curved extending section; a first cutting surfacewhich forms grooves on the second curved outer surface, and which isconfigured to cut a treated target; a second cutting surface which formsgrooves on the third curved outer surface, and which is configured tocut the treated target, the second cutting surface being different fromthe first cutting surface in extending pattern of the grooves; and athird cutting surface which forms grooves on the fourth curved outersurface, and which is configured to cut the treated target, the thirdcutting surface being different from the first cutting surface inextending pattern of the grooves.

Advantages of the invention will be set forth in the description whichfollows, and in part will be obvious from the description, or may belearned by practice of the invention. The advantages of the inventionmay be realized and obtained by means of the instrumentalities andcombinations particularly pointed out hereinafter.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

The accompanying drawings, which are incorporated in and constitute apart of the specification, illustrate embodiments of the invention, andtogether with the general description given above and the detaileddescription of the embodiments given below, serve to explain theprinciples of the invention.

FIG. 1 is a view showing an ultrasonic treatment device according to afirst embodiment of the present invention;

FIG. 2 is a schematic view of a vibrating body unit according to thefirst embodiment seen from a first width direction side;

FIG. 3 is a schematic view of a distal portion of an ultrasonic probeaccording to the first embodiment seen from the first width directionside;

FIG. 4 is a schematic view of the distal portion of the ultrasonic probeaccording to the first embodiment seen from a second intersectingdirection side;

FIG. 5 is a schematic view of a second curved extending sectionaccording to the first embodiment seen from a direction of an arrow V ofFIG. 3;

FIG. 6 is a schematic view of the second curved extending sectionaccording to the first embodiment seen from a first width directionside;

FIG. 7 is a cross-sectional view along the VII-VII line of FIG. 3;

FIG. 8 is a schematic view of a state where a bone is cut in a shoulderjoint by use of an ultrasonic treatment device according to the firstembodiment, which is seen from a front side of the shoulder joint;

FIG. 9 is a schematic view of a state where the bone is cut in theshoulder joint by use of the ultrasonic treatment device according tothe first embodiment, which is seen from a rear side of the shoulderjoint;

FIG. 10 is a schematic view showing a state where a first cuttingsurface of a curved extending section of the ultrasonic probe accordingto the first embodiment is in contact with a lower surface of anacromion;

FIG. 11 is a schematic view showing a state where the first cuttingsurface of the curved extending section of the ultrasonic probeaccording to the first embodiment is in contact with a positiondifferent from that of FIG. 10 in the lower surface of the acromion; and

FIG. 12 is a schematic view showing an amplitude of a longitudinalvibration and stress due to an ultrasonic vibration between a seconddistal vibration antinode and a most distal vibration antinode in astate where the vibrating body unit according to the first embodimentlongitudinally vibrates in an established frequency range.

DETAILED DESCRIPTION OF THE INVENTION First Embodiment

A first embodiment of the present invention will be described withreference to FIG. 1 to FIG. 12. FIG. 1 is a view showing an ultrasonictreatment system 1 of the present embodiment. As shown in FIG. 1, theultrasonic treatment system 1 includes an ultrasonic treatmentinstrument (a hand piece) 2, an energy control device 3, and atransducer unit 5. The ultrasonic treatment instrument 2 has alongitudinal axis C. Here, a direction parallel to the longitudinal axisC is a longitudinal axis direction. One side of the longitudinal axisdirection is a distal side (an arrow C1 side of FIG. 1), and a sideopposite to the distal side is a proximal side (an arrow C2 side of FIG.1).

The ultrasonic treatment tool 2 includes a holding unit 6, a sheath 7,and an ultrasonic probe 8. The holding unit 6 includes a holding casing11 to be held by an operator, and an energy operating button 12 that isan energy operation input section attached to the holding casing 11 andconfigured to be operated by the operator. The sheath 7 that is a hollowtubular member extending along the longitudinal axis C is coupled withthe distal side of the holding unit 6. The ultrasonic probe (a vibrationtransmitting member) 8 is inserted through the sheath 7. It is to benoted that a distal portion of the ultrasonic probe 8 projects from adistal end of the sheath 7 toward the distal side.

Furthermore, the transducer unit 5 having a transducer case 13 iscoupled with the proximal side of the holding unit 6. The oscillatorunit 5 is connected to one end of a cable 15. The other end of the cable15 is connected to the energy control device 3. The energy controldevice 3 includes an electric power source, a conversion circuit toconvert an electric power from the electric power source into avibration generating electric power, a processor (a control section)including a CPU (central processing unit) or an ASIC (applicationspecific integrated circuit), and a storage medium such as a memory.Inside the holding casing 11, there is disposed a switch (not shown) inwhich an ON/OFF state is changed by an input of an energy operation inthe energy operating button 12. The switch is electrically connected tothe processor of the energy control device 3 via a signal routeextending through the vibrator unit 5 and an inside of the cable 15.Furthermore, in the ultrasonic treatment system 1, a vibrating body unit20 extends through an inside of the holding casing 11 and an inside ofthe transducer case 13.

FIG. 2 is a view showing a constitution of the vibrating body unit 20.As shown in FIG. 2, the vibrating body unit 20 includes the ultrasonicprobe 8 mentioned above, an ultrasonic transducer 21 that is a vibrationgenerating section constituted of piezoelectric elements, and a relaytransmitting member 22. The ultrasonic oscillator 21 and the relaytransmitting member 22 are arranged in the oscillator case 13, and therelay transmitting member 22 is supported by the transducer case 13. Theultrasonic transducer 21 is attached to the relay transmitting member22. Inside the holding casing 11, the ultrasonic probe 8 is connected tothe distal side of the relay transmitting member 22. In the relaytransmitting member 22, a sectional area changing portion 23 is disposedin which a sectional area perpendicular to the longitudinal axis Cdecreases toward the distal side. The sectional area changing portion (ahorn portion) 23 is positioned on the distal side with respect to theultrasonic transducer 21. The ultrasonic transducer 21 is connected toone end of each of electric wires 25A and 25B. The electric wires 25Aand 25B extend through the inside of the cable 15, and the other end ofthe wire is connected to the energy control device 3.

The switch is switched to an ON state by the input of the energyoperation in the energy operating button 12, whereby in the energycontrol device 3, the control section controls the conversion circuit,to supply the vibration generating electric power (a vibrationgenerating current) to the ultrasonic vibrator 21 through the electricwires 25A and 25B. Consequently, in the ultrasonic transducer 21, anultrasonic vibration occurs, and the generated ultrasonic vibration istransmitted to the ultrasonic probe 8 via the relay transmitting member22. In this case, an amplitude of the ultrasonic vibration is enlargedin the sectional area changing portion 23 of the relay transmittingmember 22.

The ultrasonic probe 8 includes a probe main body section 31 extendingalong the longitudinal axis C. The probe main body section 31substantially linearly extends along the longitudinal axis C which is anaxial center. On the proximal side of the probe main body section 31, anengagement connecting portion 32 is provided. The engagement connectingportion 32 is engaged in an engagement groove (not shown) disposed inthe relay transmitting member 22 (e.g., by screwing an external threadinto an internal thread), whereby the probe main body section 31 isconnected to the distal side of the relay transmitting member 22. Thus,the relay transmitting member 22 is connected to the probe main bodysection 31, whereby an abutment surface 33 formed at a proximal end ofthe probe main body section 31 abuts on the relay transmitting member22. The ultrasonic vibration is transmitted from the relay transmittingmember 22 to the probe main body section 31 through the abutment surface33.

Thus, the ultrasonic vibration is transmitted to the probe main bodysection 31, whereby in the probe main body section 31 (the ultrasonicprobe 8), the ultrasonic vibration is transmitted from the proximal sidetoward the distal side. In a state where the ultrasonic vibration istransmitted through the probe main body section 31, the vibrating bodyunit 20 performs a longitudinal vibration in a vibrating directionparallel to the longitudinal axis direction in an established frequencyrange including an established frequency. In this case, a vibrationantinode (the most proximal vibration antinode) A1 that is one ofvibration antinodes of the longitudinal vibration is positioned at aproximal end of the vibrating body unit 20 (a proximal end of the relaytransmitting member 22), and a vibration antinode (the most distalvibration antinode) A2 that is one of the vibration antinodes of thelongitudinal vibration is positioned at a distal end of the vibratingbody unit 20 (a distal end of the ultrasonic probe 8). Here, thevibration antinode A1 is positioned most proximally among the vibrationantinodes of the longitudinal vibration, and the vibration antinode A2is positioned most distally among the vibration antinodes of thelongitudinal vibration. In a certain example, the vibrating body unit 20is designed in a state of transmitting the ultrasonic vibrationtherethrough, thereby performing the longitudinal vibration at 47 kHz(the established frequency), and the vibrating body unit actuallylongitudinally vibrates in the frequency range (the establishedfrequency range) of 46 kHz or more and 48 kHz or less.

The ultrasonic probe 8 has a total length L1 from its distal end to itsproximal end (a proximal end of the engagement connecting portion 32) inthe longitudinal axis direction. In the certain example, it ispreferable that the total length L1 is 182.9 mm. Furthermore, theultrasonic probe 8 has a longitudinal dimension L2 from the distal endto the abutment surface 33 (the proximal end of the probe main bodysection 31) in the longitudinal axis direction. In the certain example,it is preferable that the longitudinal dimension L2 is 177.5 mm.

In the probe main body section 31, a horn portion (a first horn portion)35 is disposed. In the horn portion 35, the sectional area perpendicularto the longitudinal axis C decreases toward the distal side. The hornportion (a sectional area decreasing portion) 35 is positioned on thedistal side with respect to the abutment surface 33, and the probe mainbody section 31 has a longitudinal dimension L3 from the abutmentsurface 33 to a proximal end (a vibration input end) E1 of the hornportion 35 in the longitudinal axis direction. In the certain example,it is preferable that the longitudinal dimension L3 is 29 mm.Furthermore, the horn portion (the first horn portion) 35 has a hornlongitudinal dimension (a first horn longitudinal dimension) L4 from theproximal end (the vibration input end) E1 to a distal end (a vibrationoutput end) E2 in the longitudinal axis direction. In the certainexample, it is preferable that the horn longitudinal dimension L4 is 20mm.

An outer diameter of the probe main body section 31 is kept to besubstantially constant from the abutment surface 33 to the proximal endE1 of the horn portion 35 in the longitudinal axis direction. Therefore,the probe main body section 31 has an outer diameter D1 in the abutmentsurface 33 and at the proximal end E1 of the horn portion 35. In thecertain example, it is preferable that the outer diameter D1 is 7 mm.Furthermore, in the horn portion 35, a sectional area decreases towardthe distal side, and hence at the distal end E2 of the horn portion 35,the probe main body section 31 has an outer diameter D2 smaller than theouter diameter D1. That is, in the horn portion 35, the outer diameterof the probe main body section 31 decreases from the outer diameter D1to the outer diameter D2 toward the distal side. In the certain example,it is preferable that the outer diameter D2 is 3.8 mm.

In a state where the vibrating body unit 20 longitudinally vibrates inthe predetermined frequency range (e.g., 46 kHz or more and 48 kHz orless), a vibration node N1 that is one of vibration nodes of thelongitudinal vibration is positioned at the proximal end E1 of the hornportion 35 or in the vicinity of the proximal end E1, and each of thevibration antinodes of the longitudinal vibration is positioned awayfrom the horn portion 35 in the longitudinal axis direction.Consequently, in the horn portion 35 in which the sectional areadecreases toward the distal side, the amplitude of the longitudinalvibration (the ultrasonic vibration) is enlarged. In the certainexample, the longitudinal vibration in which the amplitude at thevibration antinode is 18 μm is transmitted to the proximal end E1 of thehorn portion 35, and the amplitude of the longitudinal vibration in thehorn portion 35 is enlarged. It is to be noted that in a state where thevibrating body unit 20 longitudinally vibrates at the predeterminedfrequency (e.g., 47 kHz) included in the predetermined frequency range,the vibration node N1 is positioned at the proximal end E1 of the hornportion 35.

In the probe main body section 31, a horn portion (a second hornportion) 36 is provided. In the horn portion 36, the sectional areaperpendicular to the longitudinal axis C decreases toward the distalside. The horn portion (a sectional area decreasing portion) 36 ispositioned on the distal side from the horn portion (the first hornportion) 35, and the probe main body section 31 has a longitudinaldimension L5 from the abutment surface 33 to a proximal end (a vibrationinput end) E3 of the horn portion 36 in the longitudinal axis direction.In the certain example, it is preferable that the longitudinal dimensionL5 is 88.1 mm. Furthermore, the horn portion (the second horn portion)36 has a horn longitudinal dimension (a second horn longitudinaldimension) L6 from the proximal end (the vibration input end) E3 to adistal end (a vibration output end) E4 in the longitudinal axisdirection. In the certain example, it is preferable that the hornlongitudinal dimension L6 is 14 mm.

In the probe main body section 31, the outer diameter is kept to besubstantially constant from the distal end E2 of the horn portion (thefirst horn portion) 35 to the proximal end E3 of the horn portion (thesecond horn portion) 36 in the longitudinal axis direction. Therefore,the probe main body section 31 has the outer diameter D2 at the proximalend E3 of the horn portion 36. That is, at the distal end E2 of the hornportion 35 and the proximal end E3 of the horn portion 36, the outerdiameter of the probe main body section 31 becomes the outer diameter D2and has about the same size. Furthermore, in the horn portion 36, thesectional area decreases toward the distal side, and hence at the distalend E4 of the horn portion 36, the probe main body section 31 has anouter diameter D3 that is smaller than the outer diameter D2. That is,in the horn portion 36, the outer diameter of the probe main bodysection 31 decreases from the outer diameter D2 to the outer diameter D3toward the distal side. In the certain example, it is preferable thatthe outer diameter D3 is 2.7 mm.

In the state where the vibrating body unit 20 longitudinally vibrates inthe established frequency range (e.g., 46 kHz or more and 48 kHz orless), a vibration node N2 that is one of the vibration nodes of thelongitudinal vibration is positioned at the proximal end E3 of the hornportion 36 or in the vicinity of the proximal end E3, and each of thevibration antinodes of the longitudinal vibration is positioned awayfrom the horn portion 36 in the longitudinal axis direction.Consequently, in the horn portion 36 in which the sectional areadecreases toward the distal side, the amplitude of the longitudinalvibration (the ultrasonic vibration) is enlarged. It is to be noted thatin the state where the vibrating body unit 20 longitudinally vibrates atthe established frequency (e.g., 47 kHz) included in the establishedfrequency range, the vibration node N2 is positioned at the proximal endE3 of the horn portion 36. Furthermore, in the state where the vibratingbody unit 20 longitudinally vibrates in the predetermined frequencyrange, the vibration node N2 is positioned on the distal side withrespect to the vibration node N1.

In the probe main body section 31, a sectional area increasing portion37 is provided. In the sectional area increasing portion 37, thesectional area perpendicular to the longitudinal axis C increases towardthe distal side. The sectional area increasing portion 37 is positionedon the distal side with respect to the horn portion (the second hornportion) 36, and the probe main body section 31 has a longitudinaldimension L7 from the abutment surface 33 to a distal end (a vibrationoutput end) E6 of the sectional area increasing portion 37 in thelongitudinal axis direction. In the certain example, it is preferablethat the longitudinal dimension L7 is 116.7 mm. Furthermore, thesectional area increasing portion 37 has an extending dimension L8 froma proximal end (a vibration input end) E5 to the distal end (thevibration output end) E6 in the longitudinal axis direction. Theextending dimension L8 is small, and hence in the sectional areaincreasing portion 37, a distance from the proximal end E5 to the distalend E6 decreases.

In the probe main body section 31, the outer diameter is kept to besubstantially constant from the distal end E4 of the horn portion (thesecond horn portion) 36 to the proximal end E5 of the sectional areaincreasing portion 37 in the longitudinal axis direction. Therefore, theprobe main body section 31 has the outer diameter D3 at the proximal endE5 of the sectional area increasing portion 37. That is, at the distalend E4 of the horn portion 36 and the proximal end E5 of the sectionalarea increasing portion 37, the outer diameter of the probe main bodysection 31 becomes the outer diameter D3 and has about the same size.Furthermore, in the sectional area increasing portion 37, the sectionalarea increases toward the distal side, and hence at the distal end E6 ofthe sectional area increasing portion 37, the probe main body section 31has an outer diameter D4 that is larger than the outer diameter D3. Thatis, in the sectional area increasing portion 37, the outer diameter ofthe probe main body section 31 increases from the outer diameter D3 tothe outer diameter D4 toward the distal side. In the certain example,the outer diameter D4 is about the same as the outer diameter D2 at theproximal end E3 of the horn portion 36. In this case, it is preferablethat the outer diameter D4 is 3.8 mm.

In the state where the vibrating body unit 20 longitudinally vibrates inthe established frequency range, a vibration antinode A3 that is one ofthe vibration antinodes of the longitudinal vibration is positioned inthe sectional area increasing portion 37. The vibration antinode A3 atwhich stress due to the ultrasonic vibration becomes zero is positionedin the sectional area increasing portion 37, and hence, also in thesectional area increasing portion 37 in which the sectional areaincreases toward the distal side, the amplitude of the longitudinalvibration (the ultrasonic vibration) hardly decreases. It is to be notedthat in the state where the vibrating body unit 20 longitudinallyvibrates in the established frequency range, the vibration antinode A3is positioned on the distal side with respect to the vibration node N2,and in the present embodiment, the vibration antinode A3 is positionedsecond distally among the vibration antinodes of the longitudinalvibration.

The probe main body section 31 includes a supported portion 38 to besupported by the sheath 7 via an elastic member (not shown). Thesupported portion 38 is positioned on the distal side with respect tothe sectional area increasing portion 37. The probe main body section 31has a longitudinal dimension L9 from the distal end E6 of the sectionalarea increasing portion 37 to a proximal end E7 of the supported portion38 in the longitudinal axis direction. In the certain example, it ispreferable that the longitudinal dimension L9 is 24.1 mm. Furthermore,the supported portion 38 has an extending dimension L10 from theproximal end E7 to a distal end E8 in the longitudinal axis direction.The extending dimension L10 is small, and in the certain example, it ispreferable that the extending dimension L10 is 3 mm.

In the probe main body section 31, the outer diameter is kept to besubstantially constant from the distal end E6 of the sectional areaincreasing portion 37 to the proximal end E7 of the supported portion 38in the longitudinal axis direction. Therefore, the probe main bodysection 31 has the outer diameter D4 at the proximal end E7 of thesupported portion 38. That is, at the distal end E6 of the sectionalarea increasing portion 37 and the proximal end E7 of the supportedportion 38, the outer diameter of the probe main body section 31 becomesthe outer diameter D4 and has about the same size. In a proximal portionof the supported portion 38, the outer diameter of the probe main bodysection 31 decreases from the outer diameter D4 to an outer diameter D5.In the certain example, the outer diameter D5 is about 0.4 mm smallerthan the outer diameter D4. In the supported portion 38, the outerdiameter of the probe main body section 31 is kept to be substantiallyconstant at the outer diameter D5 along a large part in the longitudinalaxis direction. Further, in the distal portion of the supported portion38, the outer diameter of the probe main body section 31 increases fromthe outer diameter D5 to an outer diameter D6. In consequence, the probemain body section 31 has the outer diameter D6 at the distal end E8 ofthe supported portion 38. The outer diameter D6 at the distal end E8 ofthe supported portion 38 is about the same as the outer diameter D4 atthe proximal end E7 of the supported portion 38. Consequently, at theproximal end E7 and the distal end E8 of the supported portion 38, thesectional area of the probe main body section 31 which is perpendicularto the longitudinal axis C becomes about the same. In the certainexample, it is preferable that the outer diameter D6 is 3.8 mm.

In the state where the vibrating body unit 20 longitudinally vibrates inthe established frequency range, a vibration node N3 that is one of thevibration nodes of the longitudinal vibration is positioned in thesupported portion 38. Consequently, the probe main body section 31 (theultrasonic probe 8), which longitudinally vibrates, is also attached tothe sheath 7 via the elastic member in the supported portion 38.Furthermore, the probe main body section is supported by the sheath 7 atthe vibration node N3 of the longitudinal vibration, and hence in thestate where the vibrating body unit 20 longitudinally vibrates in thepredetermined frequency range, transmission of the ultrasonic vibrationfrom the supported portion 38 to the sheath 7 is prevented. In the statewhere the vibrating body unit 20 longitudinally vibrates in theestablished frequency range, the vibration node (the most distalvibration node) N3 is positioned on the distal side with respect to thevibration node N2, and is positioned most distally among the vibrationnodes of the longitudinal vibration. Furthermore, at the proximal end E7and the distal end E8 of the supported portion 38, the sectional area ofthe probe main body section 31 which is perpendicular to thelongitudinal axis C becomes about the same, and hence in the supportedportion 38, the amplitude of the longitudinal vibration hardly changes.

Furthermore, the distal end of the sheath 7 is positioned on the distalside from the distal end E8 of the supported portion 38. Therefore, inthe state where the vibrating body unit 20 longitudinally vibrates inthe established frequency range, the vibration node N3 positioned mostdistally among the vibration nodes is positioned inside the sheath 7.

FIG. 3 and FIG. 4 are views showing a constitution of the distal portionof the ultrasonic probe 8. Here, a certain direction that intersects (issubstantially perpendicular to) the longitudinal axis C is a firstintersecting direction (a direction of an arrow P1 in each of FIG. 2 andFIG. 3), and an opposite direction to the first intersecting direction(a first vertical direction) is a second intersecting direction (adirection of an arrow P2 in each of FIG. 2 and FIG. 3). Furthermore, oneof two directions which intersect the longitudinal axis C (substantiallyperpendicularly) and are perpendicular to (intersect) the firstintersecting direction (the first perpendicular direction) and thesecond intersecting direction (a second perpendicular direction) is afirst width direction (a direction of an arrow B1 in FIG. 4). Further,an opposite direction to the first width direction is a second widthdirection (a direction of an arrow B2 in FIG. 4). Here, FIG. 2 and FIG.3 are views of the ultrasonic probe 8 seen from a first width directionside, and FIG. 4 is a view of the ultrasonic probe 8 seen from a secondperpendicular direction side. It is to be noted that in FIG. 3, a rangeshown by a broken line S1 and a broken line S2 projects from the distalend of the sheath 7 toward the distal side.

As shown in FIG. 3 and FIG. 4, the probe main body section 31 extends toa position located on the distal side with respect to the supportedportion 38. That is, a distal end E9 of the probe main body section 31is positioned on the distal side from the distal end E8 of the supportedportion 38. However, a distance between the distal end E8 of thesupported portion 38 and the distal end E9 of the probe main bodysection 31 in the longitudinal axis direction is small, and is about 0.6mm in the certain example.

As described above, in the probe main body section 31, the amplitude ofthe longitudinal vibration is enlarged in the horn portion (the firsthorn portion) 35 and the horn portion (the second horn portion) 36, andthe amplitude of the longitudinal vibration hardly changes in thesectional area increasing portion 37 and the supported portion 38. Dueto the above-mentioned constitution, in the certain example, thelongitudinal vibration of an amplitude of 80 μm occurs at the distal endE9 of the probe main body section 31, in a case where the longitudinalvibration of an amplitude of 18 μm at the vibration antinode istransmitted to the proximal end (the abutment surface 33) of the probemain body section 31.

A tapered section (a sectional area decreasing portion) 41 is continuouson the distal side of the probe main body section 31. In the taperedsection (a third horn portion) 41, a sectional area perpendicular to alongitudinal axis C decreases toward the distal side. A proximal end ofthe tapered section 41 is continuous with the distal end E9 of the probemain body section 31. Therefore, the distal end E9 of the probe mainbody section 31 becomes a boundary position between the probe main bodysection 31 and the tapered section 41. The ultrasonic probe 8 has alongitudinal dimension L11 from the distal end to the proximal end (E9)of the tapered section 41 in the longitudinal axis direction. In thecertain example, it is preferable that the longitudinal dimension L11 is32.5 mm.

The tapered section 41 includes a first narrowed outer surface 51 facinga first intersecting direction side. In the tapered section 41, adistance (a first distance) δ from the longitudinal axis C to the firstnarrowed outer surface 51 in a first intersecting direction decreasesfrom a proximal side toward the distal side, between the proximal end(E9) and a first narrowing end position (a first distance decreasing endposition) E10 in the longitudinal axis direction. The first narrowingend position E10 is positioned on the distal side with respect to theproximal end (E9) of the tapered section 41. Consequently, the taperedsection 41 has a first narrowing dimension (a first distance decreasingdimension) L12 between the proximal end (E9) and the first constrictingend position E10 in the longitudinal axis direction. In the certainexample, it is preferable that the first narrowing dimension L12 is 18mm. In the present embodiment, the proximal end (E9) of the taperedsection 41 becomes a proximal end of the first narrowed outer surface51, and the first narrowing end position E10 becomes a distal end of thefirst narrowed outer surface 51.

Furthermore, the tapered section 41 includes a second narrowed outersurface 52 facing the second intersecting direction side. On the taperedsection 41, a distance (a second distance) δ′ from the longitudinal axisC to the second narrowed outer surface 52 in a second intersectingdirection decreases from the proximal side toward the distal side,between the proximal end (E9) and a second narrowing end position (asecond distance decreasing end position) E11 in the longitudinal axisdirection. The second narrowing end position E11 is positioned on thedistal side with respect to the first narrowing end position E10.Consequently, the tapered section 41 has a second narrowing dimension (asecond distancing decrease dimension) L13 that is larger than the firstnarrowing dimension L12, between the proximal end (E9) and the secondnarrowing end position E11 in the longitudinal axis direction. In thecertain example, it is preferable that the second constricting dimensionL13 is 23 mm. In the present embodiment, the proximal end (E9) of thetapered section 41 becomes a proximal end of the second narrowed outersurface 52, and the second narrowing end position E11 becomes a distalend of the second constricted outer surface 52. Consequently, in thetapered section 41, the distal end of the first constricted outersurface 51 (the first constricting end position E10) is positioned on aproximal side as compared with the distal end of the second narrowedouter surface 52 (the second narrowing end position E11), and the distalend of the first narrowed outer surface 51 is disposed away from thedistal end of the second narrowed outer surface 52 in the longitudinalaxis direction.

Due to the above-mentioned constitution, in the tapered section 41, athickness (a dimension) T of the ultrasonic probe 8 in the firstintersecting direction and the second intersecting direction decreasestoward the distal side, between the proximal end (E9) and the secondnarrowing end position E11 in the longitudinal axis direction.Therefore, the proximal end (E9) of the tapered section 41 becomes athickness decreasing start position, and the second narrowing endposition E11 becomes a thickness decreasing end position. Furthermore,in projection from a first width direction (one side of a widthdirection), a first narrowing angle α1 that is a narrowing angle (anacute angle) of the first narrowed outer surface 51 relative to thelongitudinal axis direction is larger than a second narrowing angle α2that is a narrowing angle (an acute angle) of the second narrowed outersurface 52 relative to the longitudinal axis direction, and the firstnarrowing angle is different from the second narrowing angle α2.

Furthermore, the tapered section 41 includes a third narrowed outersurface 53 directed in the first width direction, and a fourth narrowedouter surface 54 facing a second width direction. In the tapered section41, between a width decreasing start position E12 and a width decreasingend position E13 in the longitudinal axis direction, a distance from thelongitudinal axis C to the third narrowed outer surface 53 in the firstwidth direction and a distance from the longitudinal axis C to thefourth narrowed outer surface 54 in the second width direction decreasefrom the proximal side toward the distal side. Consequently, in thetapered section 41, a width (a dimension) W of the ultrasonic probe 8 inthe first width direction and the second width direction decreasestoward the distal side, between the width decreasing start position E12and the width decreasing end position E13 in the longitudinal axisdirection. The ultrasonic probe 8 has a longitudinal dimension L14 fromthe distal end to the width decreasing start position E12 in thelongitudinal axis direction. The longitudinal dimension L14 is smallerthan the longitudinal dimension L11 from the distal end of theultrasonic probe 8 to the proximal end (E9) of the tapered section 41 inthe longitudinal axis direction. Therefore, the width decreasing startposition E12 is positioned on the distal side with respect to theproximal end (E9) of the tapered section 41. However, the distancebetween the proximal end (E9) of the tapered section 41 and the widthdecreasing start position E12 in the longitudinal axis direction issmall. In the certain example, it is preferable that the longitudinaldimension L14 is 32 mm. Further, in this example, the distance betweenthe proximal end (E9) of the tapered section 41 and the width decreasingstart position E12 in the longitudinal axis direction is about 0.5 mm.In the present embodiment, the width decreasing start position E12becomes a proximal end of each of the third constricted outer surface 53and the fourth constricted outer surface 54, and the width decreasingend position E13 becomes a distal end of each of the third narrowedouter surface 53 and the fourth narrowed outer surface 54.

The ultrasonic probe 8 has a longitudinal dimension L15 from the distalend to the width decreasing end position E13 in the longitudinal axisdirection. In the present embodiment, the width decreasing end positionE13 is positioned on the distal side with respect to the secondnarrowing end position E11. Further, the width decreasing end positionE13 becomes a distal end of the tapered section 41. However, a distancebetween the second narrowing end position (the distal end of the secondnarrowed outer surface 52) E11 and the width decreasing end position E13in the longitudinal axis direction is small. In the certain example, itis preferable that the longitudinal dimension L15 is 9 mm. Further, inthis example, the distance between the second narrowing end position E11and the width decreasing end position E13 in the longitudinal axisdirection is about 0.5 mm.

The distance (the first distance) δ from the longitudinal axis C to thefirst narrowed outer surface 51 (an outer peripheral surface of theultrasonic probe 8) in the first intersecting direction (a firstperpendicular direction) decreases down to a distance δ1, between theproximal end (E9) of the tapered section 41 and the first narrowing endposition E10 in the longitudinal axis direction. Therefore, at the firstnarrowing end position (the distal end of the first narrowed outersurface 51) E10, the ultrasonic probe 8 has the distance (the firstdistance) δ1 from the longitudinal axis C to the first narrowed outersurface 51 toward the first intersecting direction. The distance δ1 issmaller than a value of ½ of the outer diameter D6 at the distal end E9of the probe main body section 31. In the certain example, the distanceδ1 is 0.45 mm or more and 0.5 mm or less.

Between the proximal end (E9) of the tapered section 41 and the secondnarrowing end position E11 in the longitudinal axis direction, thethickness (the dimension) T of the ultrasonic probe 8 in the firstintersecting direction and the second intersecting direction decreasesdown to a thickness T1. Therefore, at the second narrowing end position(the distal end of the second narrowed outer surface 52) E11, theultrasonic probe 8 has the thickness T1 in the first intersectingdirection (the first perpendicular direction) and the secondintersecting direction (a second perpendicular direction). The thicknessT1 is smaller than the outer diameter D6 at the distal end E9 of theprobe main body section 31. In the certain example, it is preferablethat the thickness T1 is 1.65 mm.

Between the width decreasing start position E12 and the width decreasingend position E13 in the longitudinal axis direction, the width (thedimension) W of the ultrasonic probe 8 in the first width direction andthe second width direction decreases down to a width dimension W1.Therefore, at the width decreasing end position (the distal end of eachof the third constricted outer surface 53 and the fourth constrictedouter surface 54) E13, the ultrasonic probe 8 has the width dimension W1in the first width direction and the second width direction. The widthdimension W1 is smaller than the outer diameter D6 at the distal end E9of the probe main body section 31. In the certain example, it ispreferable that the width dimension W1 is 2.8 mm.

The tapered section 41 is constituted as described above, and hence inthe tapered section 41, the sectional area perpendicular to thelongitudinal axis C decreases toward the distal side. In the state wherethe vibrating body unit 20 longitudinally vibrates in the establishedfrequency range (e.g., 46 kHz or more and 48 kHz or less), the vibrationnode (the most distal vibration node) N3 that is one of the vibrationnodes of the longitudinal vibration is positioned in the supportedportion 38, and is positioned in the vicinity of the proximal end (E9)of the tapered section 41. Further, in the state where the vibratingbody unit 20 longitudinally vibrates in the predetermined frequencyrange, each of the vibration antinodes of the longitudinal vibration ispositioned away from the tapered section 41 in the longitudinal axisdirection. Consequently, in the tapered section 41 in which thesectional area decreases toward the distal side, the amplitude of thelongitudinal vibration (ultrasonic vibration) is enlarged. In thecertain example, in a case where the longitudinal vibration in which theamplitude in the tapered section 41 is 80 μm is transmitted, theamplitude of the longitudinal vibration at the distal end of theultrasonic probe 8 is 140 μm or more and 150 μm or less.

Furthermore, in the present embodiment, a tapering dimension of thetapered section 41 from the proximal end (E9) to the distal end (E13) inthe longitudinal axis direction is larger than a ⅛ wavelength (λ/8) inthe state where the vibrating body unit 20 longitudinally vibrates inthe established frequency range. That is, the ⅛ wavelength (λ/8) in thestate where the vibrating body unit 20 longitudinally vibrates in theestablished frequency range is smaller than the tapering dimension ofthe tapered section 41 from the proximal end (E9) to the distal end(E13) in the longitudinal axis direction. In the certain example, in thestate where the vibrating body unit 20 longitudinally vibrates at 46 kHzor more and 48 kHz or less (in the established frequency range), a ¼wavelength (λ/4) from the vibration node (the most distal vibrationnode) N3 to the vibration antinode (the most distal vibration antinode)A2 is 34 mm or more and 35 mm or less. On the other hand, in thisexample, the tapering dimension of the tapered section 41 from theproximal end (E9) to the distal end (E13) in the longitudinal axisdirection is about 23.5 mm, and is larger than the ⅛ wavelength in thestate where the vibrating body unit 20 longitudinally vibrates at 46 kHzor more and 48 kHz or less (in the predetermined frequency range).Furthermore, in the tapered section 41, the first narrowing dimensionL12 between the proximal end (E9) and the first narrowing end positionE10 in the longitudinal axis direction is also 17.9 mm or more and 18 mmor less. Therefore, the first narrowing dimension L12 (i.e., thedimension of the first constricted outer surface 51 in the longitudinalaxis direction) is also larger than the ⅛ wavelength in the state wherethe vibrating body unit 20 longitudinally vibrates at 46 kHz or more and48 kHz or less (in the established frequency range). It is to be notedthat the first narrowing end position E10 is positioned most proximallyamong the positions (e.g., E10, E11 and E13) at which the narrowing endson an outer peripheral surface of the tapered section 41 (the narrowedouter surfaces 51 to 54).

In the ultrasonic probe 8, a curved extending section 40 is disposed onthe distal side with respect to the tapered section 41 (and the probemain body section 31).

The curved extending section 40 extends in a state of curving relativeto the probe main body section 31 and the tapered section 41 (i.e., thelongitudinal axis C) toward the first intersecting direction side. Thecurved extending section 40 includes a first curved outer surface 55facing the first intersecting direction side (a side on which the curvedextending section 40 curves), and a second curved outer surface 56directed on the second intersecting direction side (a side opposite tothe side on which the curve extending section 40 curves). Furthermore,the curved extending section 40 includes a third curved outer surface 57facing the first width direction side, and a fourth curved outer surface58 facing on a second width direction side. It is to be noted that bytransmitting the ultrasonic vibration to the curved extending section 40from the probe main body section 31 through the tapered section 41, thecurved extending section 40 longitudinally vibrates together with theprobe main body section 31 and the tapered section 41 in the establishedfrequency range.

In projection from the first width direction (one side of the widthdirection), in the first curved outer surface 55 of the curved extendingsection 40, a region located on the distal side with respect to a firstcurve start position E14 curves relative to the longitudinal axisdirection (the probe main body section 31) toward the first intersectingdirection side. Furthermore, in the projection from the first widthdirection, in the second curved outer surface 56 of the curved extendingsection 40, a region located on the distal side with respect to a secondcurve start position E15 curves relative to the longitudinal axisdirection toward the first intersecting direction side. That is, thefirst curved outer surface 55 starts curving relative to thelongitudinal axis C in the first intersecting direction side at thefirst curve start position E14, and the second curved outer surface 56starts curving relative to the longitudinal axis C toward the firstintersecting direction side at the second curve start position E15. Inthe present embodiment, the second curve start position (a proximal endof the second curved outer surface 56) E15 is positioned on the distalside with respect to the first curve start position (a proximal end ofthe first curved outer surface 55) E14, and is positioned away from thefirst curve start position E14 in the longitudinal axis direction.Additionally, in the present embodiment, a distance between the firstcurve start position E14 and the second curve start position E15 in thelongitudinal axis direction is small, and is about 0.3 mm in the certainexample.

The curved extending section 40 extends toward the distal side from thefirst curve start position E14 which is the proximal end (a curveproximal end). The ultrasonic probe 8 has a longitudinal dimension L16from the distal end to the proximal end (E14) of the curved extendingsection 40 in the longitudinal axis direction. The longitudinaldimension L16 is smaller than the longitudinal dimension L15 from thedistal end of the ultrasonic probe 8 to the width decreasing endposition E13 in the longitudinal axis direction. Consequently, theproximal end (E14) of the curved extending section 40 is positioned onthe distal side with respect to the width decreasing end position E13.In the certain example, the longitudinal dimension L16 is 8.4 mm or moreand 8.5 mm or less.

Furthermore, in the ultrasonic probe 8, a relay extending section 43 iscontinuous between the tapered section 41 and the curved extendingsection 40 in the longitudinal axis direction. The relay extendingsection 43 extends from the width decreasing end position E13 (thedistal end of the tapered section 41) to the first curve start positionE14 (a proximal end of the curved extending section 40). Here, adistance between the width decreasing end position E13 and the proximalend (E14) of the curved extending section 40 in the longitudinal axisdirection is small. Consequently, a dimension of the relay extendingsection 43 in the longitudinal axis direction is small. In the certainexample, the dimension of the relay extending section 43 in thelongitudinal axis direction is about 0.5 mm.

A first axis parallel outer surface 61 directed in the firstintersecting direction is continuous between the first narrowed outersurface 51 and the first curved outer surface 55 in the longitudinalaxis direction. The first axis parallel outer surface 61 extends inparallel (substantially parallel) with the longitudinal axis C betweenthe first narrowing end position E10 and the first curve start positionE14. Therefore, the first constricting end position E10 becomes aproximal end of the first axis parallel outer surface 61 and the firstcurve start position E14 becomes a distal end of the first axis parallelouter surface 61. Further, the first axis parallel outer surface 61 hasan extending dimension (a first extending dimension) L19 in thelongitudinal axis direction. On the first axis parallel outer surface61, the distance δ from the longitudinal axis C toward the firstintersecting direction is kept to be substantially constant at thedistance δ1, from the first narrowing end position E10 to the firstcurve start position E14.

Furthermore, a second axis parallel outer surface 62 facing the secondintersecting direction is continuous between the second narrowed outersurface 52 and the second curved outer surface 56 in the longitudinalaxis direction. The second axis parallel outer surface 62 extends inparallel (substantially parallel) with the longitudinal axis C, betweenthe second narrowing end position E11 and the second curve startposition E15. Therefore, the second constricting end position E11becomes a proximal end of the second axis parallel outer surface 62, andthe second curve start position E15 becomes a distal end of the secondaxis parallel outer surface 62. Further, the second axis parallel outersurface 62 has an extending dimension (a second extending dimension) L20in the longitudinal axis direction. The extending dimension L19 of thefirst axis parallel outer surface 61 is larger than the extendingdimension L20 of the second axis parallel outer surface 62. On thesecond axis parallel outer surface 62, the distance δ′ from thelongitudinal axis C toward the second intersecting direction is kept tobe substantially constant from the second narrowing end position E11 tothe second curve start position E15.

Due to such a constitution as described above, between the secondnarrowing end position E11 and the first curve start position (theproximal end of the curved extending section 40) E14 in the longitudinalaxis direction, the thickness T of the ultrasonic probe 8 in the firstintersecting direction and the second intersecting direction is kept tobe substantially constant at the thickness T1. Furthermore, between thewidth decreasing end position E13 and the distal end of the ultrasonicprobe 8 in the longitudinal axis direction, the width W of theultrasonic probe 8 in the first width direction and the second widthdirection is kept to be substantially constant at the width dimensionW1. Therefore, in the relay extending section 43 extending from thewidth decreasing end position E13 to the first curve start position (theproximal end of the curved extending section 40) E14, the dimensionbecomes substantially constant at the width dimension W1 andsubstantially constant at the thickness T1 along the total length in thelongitudinal axis direction. Further, in the relay extending section 43,the sectional area perpendicular to the longitudinal axis C becomessubstantially constant along the total length in the longitudinal axisdirection.

Here, there is stipulated a reference plane (a first reference plane) Y1passing along the longitudinal axis C and perpendicularly (substantiallyperpendicularly) to the first intersecting direction and the secondintersecting direction. In the relay extending section 43, the distance(the first distance) δ1 from the longitudinal axis C to the first axisparallel outer surface 61 (the outer peripheral surface of theultrasonic probe 8) toward the first intersecting direction is smallerthan a value of ½ of the thickness T1 of the ultrasonic probe 8 in thefirst intersecting direction and the second intersecting direction.Consequently, in the tapered section 41 and the relay extending section43, the ultrasonic probe 8 is nonsymmetrical about the reference planeY1 which is a central plane. Further, in the tapered section 41 and therelay extending section 43, a cross section gravity center in the crosssection perpendicular to the longitudinal axis C shifts from thelongitudinal axis C toward the second intersecting direction side.Especially, between the first narrowing end position E10 and the firstcurve start position E14, there increases the shift of the cross sectiongravity center relative to the longitudinal axis C in the secondintersecting direction side. Furthermore, there is stipulated areference plane (a second reference plane) Y2 passing along thelongitudinal axis C and perpendicularly (substantially perpendicularly)to the first width direction and the second width direction. In thetapered section 41 and the relay extending section 43, the ultrasonicprobe 8 is substantially symmetric about the reference plane Y2 which isa central plane.

The curved extending section 40 includes a first curved extendingsection 42 that extends from the first curve start position E14 at theproximal end of the curved extending section 40 toward the distal sideand curving relative to the probe main body section 31 and the taperedsection 41 toward the first intersecting direction side. In theprojection from the first width direction (one side of the widthdirection), in a region of an outer peripheral surface of the firstcurved extending section 42 which faces the first intersecting directionside, a tangent line at the first curve start position E14 has an acuteangle θ1 relative to the longitudinal axis direction. Furthermore, inthe projection from the first width direction, in a region of the outerperipheral surface of the first curved extending section 42 which isdirected on the second intersecting direction side, a tangent line atthe second curve start position E15 has an acute angle θ2 relative tothe longitudinal axis direction. The acute angle θ1 and the acute angleθ2 are larger than 0° and 10° or less. In the certain example, the acuteangle θ1 is 5°, whereas the acute angle θ2 is 7.5°. Consequently, theacute angle θ2 is larger than the acute angle θ1.

In the curved extending section 40, a second curved extending section 45is continuous with the distal side of the first curved extending section42. The second curved extending section 45 extends in a state of curvingrelative to the first curved extending section 42 toward the firstintersecting direction side. In the projection from the first widthdirection (one side of the width direction), a region of an outerperipheral surface of the second curved extending section 45 which facesthe first intersecting direction side extends in a circular shape of acurbing radius R1. Furthermore, in the projection from the first widthdirection, a region of the outer peripheral surface of the second curveextending section 45 which is directed on the second intersectingdirection side extends in a circular shape of a curving radius R2.

A center O1 of each of the circle of the curving radius R1 and thecircle of the curving radius R2 is positioned on the first intersectingdirection side with respect to the curved extending section 40 (theultrasonic probe 8). Consequently, in the projection from the firstwidth direction (the second width direction), in a region of the outerperipheral surface of the second curved extending section 45 which facesthe first intersecting direction side, an acute angle relative to thelongitudinal axis direction increases toward the distal side. Similarly,in the projection from the first width direction (the second widthdirection), in a region of the outer peripheral surface of the secondcurved extending section 45 which is directed on the second intersectingdirection side, an acute angle relative to the longitudinal axisdirection increases toward the distal side. Therefore, in the secondcurved extending section 45, the acute angle relative to thelongitudinal axis direction increases toward the distal side.

In the region of the outer peripheral surface of the second curvedextending section 45 which faces the first intersecting direction side,a tangent line at a distal end has an acute angle θ3 relative to thelongitudinal axis direction. Furthermore, in the region of the outerperipheral surface of the second curved extending section 45 which facesthe second intersecting direction side, a tangent line at a distal endhas an acute angle θ4 relative to the longitudinal axis direction. Thatis, at a distal end of the first curved outer surface 55, the curvedextending section 40 has the acute angle θ3 relative to the longitudinalaxis direction. Further, at a distal end of the second curved outersurface 56, the curved extending section 40 has the acute angle θ4relative to the longitudinal axis direction. In the certain example, thecurving radius R1 is 15 mm and the acute angle θ3 is 15°. Furthermore,the acute angle θ4 is stipulated in accordance with the curving radiusR2. For example, in a case where the curving radius R2 is 12.5 mm, theacute angle θ4 is 25°, and in a case where the curving radius R2 is 16.5mm, the acute angle θ4 is 20°. Further, in a case where the curvingradius R2 is 30 mm, the acute angle θ4 is 15°. In the certain example,on the second curved outer surface 56 (the region of the outerperipheral surface of the second curved extending section 45 which facesthe second intersecting direction side), the acute angle θ4 of thetangent line at the distal end relative to the longitudinal axisdirection is 10° or more and 30° or less, and more preferably 20° ormore and 25° or less.

Furthermore, a direction that is perpendicular (substantiallyperpendicular) to an extending direction and that is perpendicular(substantially perpendicular) to the width direction in the ultrasonicprobe 8 is a thickness direction. In the curved extending section 40,the extending direction of the ultrasonic probe 8 is not parallel to thelongitudinal axis, and hence in the curved extending section 40, thethickness direction is not parallel to the first intersecting directionand the second intersecting direction. The ultrasonic probe 8 is kept tobe substantially constant at a thickness dimension T2 in the thicknessdirection from the second curve start position E15 to the distal end inthe longitudinal axis direction. That is, between the second curve startposition E15 and the distal end of the ultrasonic probe 8, the thicknessdimension T2 that is a distance between the first curved outer surface55 and the second curved outer surface 56 is kept to be substantiallyconstant. In the certain example, the thickness dimension T2 is 1.5 mm.Therefore, the acute angles θ1 to θ4 and the curving radiuses R1 and R2are determined in a state where the thickness dimension T2 of theultrasonic probe 8 is substantially constant from the second curve startposition E15 to the distal end.

Furthermore, the region of the outer peripheral surface of the secondcurved extending section 45 which faces the first intersecting directionside has a separation distance T3 from the longitudinal axis C towardthe first intersecting direction at the distal end. In the certainexample, it is preferable that the separation distance T3 is 1.9 mm.

The second curved extending section 45 includes a distal surface 46 thatforms the distal end of the ultrasonic probe 8. In the projection fromthe first width direction (one side of the width direction), a portionbetween the first curved outer surface 55 (the region of the outerperipheral surface of the second curved extending section 45 which isdirected on the first intersecting direction side) and the distalsurface 46 is formed into a curved surface of a corner radius R3.Furthermore, in the projection from the first width direction, a portionbetween the second curved outer surface 56 (the region of the outerperipheral surface of the second curved extending section 45 which facesthe second intersecting direction side) and the distal surface 46 isformed into a curved surface of a corner radius R4. In the certainexample, the corner radius R3 is 0.5 mm and the corner radius R4 is 0.9mm. Furthermore, in projection from the second intersecting direction(one side of the intersecting direction), there is formed into a curvedsurface of a corner radius R5 each of a portion between a third curvedouter surface 57 (the region of the outer peripheral surface of thesecond curved extending section 45 which faces the first width directionside) and the distal surface 46 and a portion between a fourth curvedouter surface 58 (the region of the outer peripheral surface of thesecond curved extending section 45 which is directed on the second widthdirection side) and the distal surface 46.

FIG. 5 is a view of the second curved extending section 45 (a distalportion of the curved extending section 40) seen from a direction of anarrow V of FIG. 3, and is a view of the second curved extending section45 seen from one side of the thickness direction. Furthermore, FIG. 6 isa view of the second curved extending section 45 seen from the firstwidth direction side. Further, FIG. 7 is a cross-sectional view alongthe VII-VII line of FIG. 3, and shows a cross section perpendicular toan extending direction of the second curved extending section 45. Here,the direction of the arrow V matches a direction of rotating as much asan acute angle θ5 from the distal side toward the second intersectingdirection side in the projection from the first width direction. Theacute angle θ5 is, for example, 75°.

As shown in FIG. 3 to FIG. 7, cutting surfaces (treating surfaces) 47 to49 are disposed in the second curved extending section 45. A firstcutting surface 47 is disposed on the second curved outer surface 56 (aregion of an outer surface of the curved extending section 40 whichfaces the second intersecting direction side). Further, a second cuttingsurface 48 is provided on the third curved outer surface 57 (a region ofthe outer surface of the curved extending section 40 which is directedon the first width direction side), and a third cutting surface 49 isdisposed on the fourth curved outer surface 58 (a region of the outersurface of the curved extending section 40 which faces the second widthdirection side). After-mentioned grooves are formed in each of theabrading surfaces 47 to 49. Furthermore, each of the cutting surfaces 47to 49 extends from a distal end (the distal surface 46) of the curvedextending section 40 toward the proximal side. The first cutting surface47 is provided in the second curved extending section 45 and on thesecond curved outer surface 56. Consequently, in the projection fromeach of the first width direction and the second width direction, thefirst abrading surface 47 is formed into a circular shape in which thecenter (O1) is positioned on the first intersecting direction side withrespect to the curved extending section 40.

The second curved extending section 45 has a thickness dimension T6between the first cutting surface 47 and the first curved outer surface55 in the thickness direction of the curved extending section 40. Thethickness dimension T6 between the first abrading surface 47 and thefirst curved outer surface 55 is about the same size as the thicknessdimension T2. Furthermore, the second curved extending section 45 has awidth dimension W5 between the second cutting surface 48 (the thirdcurved outer surface 57) and the third cutting surface 49 (the fourthcurved outer surface 58) in the first width direction and the secondwidth direction. The width dimension W5 between the second abradingsurface 48 and the third abrading surface 49 is about the same size asthe width dimension W1. Consequently, in a range in which the firstcutting surface 47 extends (the second curved extending section 45), thethickness dimension T6 (T2) between the first cutting surface 47 and thefirst curved outer surface 55 in the thickness direction of the curvedextending section 40 is smaller than the width dimension W5 (W1) betweenthe third curved outer surface 57 and the fourth curved outer surface 58in the first width direction and the second width direction.

In the second cutting surface 48, a plurality of (five in the presentembodiment) extending grooves (first extending grooves) 63A to 63E areformed. Each of the extending grooves 63A to 63E extends substantiallyperpendicularly to the extending direction of the curved extendingsection 40, and extends along the thickness direction of the curvedextending section 40 in the present embodiment. Furthermore, theextending grooves 63A to 63E are lined in parallel in the extendingdirection of the curved extending section 40, and each of the extendinggrooves 63A to 63E has a space q1 between the extending groove and theadjacent extending groove (corresponding one or two of the grooves 63Ato 63E) in the extending direction of the curved extending section 40.Furthermore, the most distal extending groove 63A positioned mostdistally among the extending grooves 63A to 63E is stipulated. Thesecond curved extending section 45 has an extending dimension L17 fromthe distal end of the ultrasonic probe 8 to the most distal extendinggroove 63A in the extending direction of the curved extending section40. In the certain example, the space q1 is 0.9 mm and the extendingdimension L17 is 0.45 mm.

Furthermore, when there is stipulated the reference plane (the secondreference plane) Y2 passing along the longitudinal axis C andperpendicularly to the first width direction and the second widthdirection, a bottom position of each of the extending grooves 63A to 63Eis disposed as much as a width direction distance W2 away from thereference plane Y2 in the first width direction. In the certain example,the width direction distance W2 is 1.1 mm. Furthermore, when seen fromone side of the thickness direction (a first cutting surface 47 side),each of the extending grooves (the first extending grooves) 63A to 63Ehas a semicircular shape formed by a semicircular portion of a circlehaving a diameter φ1. In the certain example, the diameter φ1 is 0.5 mm.

In the third cutting surface 49, a plurality of (five in the presentembodiment) extending grooves (second extending grooves) 65A to 65E areformed. Each of the extending grooves 65A to 65E is substantiallysymmetric with the corresponding extending groove (corresponding one ofthe grooves 63A to 63E) about the reference plane Y2 which is thecentral plane. Consequently, similarly to the extending grooves (thefirst extending grooves) 63A to 63E, each of the extending grooves 65Ato 65E extends along the thickness direction of the curved extendingsection 40, and the space q1, the extending dimension L17, the widthdirection distance W2 and the diameter φ1 are stipulated in connectionwith the extending grooves (the second extending grooves) 65A to 65E.

Furthermore, the first cutting surface 47 is different in extendingpattern of the grooves from the second cutting surface 48 and the thirdcutting surface 49. In the first cutting surface 47, there are formed aplurality of (five in the present embodiment) inclined grooves (firstinclined grooves) 66A to 66E and a plurality of (five in the presentembodiment) inclined grooves (second inclined grooves) 67A to 67E. Eachof the inclined grooves 66A to 66E extends in a state of inclining asmuch as an acute angle (a first acute angle) θ6 relative to theextending direction of the curved extending section 40. That is, each ofthe inclined grooves (the first inclined grooves) 66A to 66E inclinesrelative to the longitudinal axis direction in projection from the firstcutting surface 47 side. Here, in the projection from the first abradingsurface 47 side, one side of an extending direction of each of theinclined grooves 66A to 66E matches a direction of rotating as much asthe acute angle θ6 from the proximal side toward the second widthdirection side. Furthermore, each of the inclined grooves 67A to 67Eextends in a state of inclining as much as an acute angle (a secondacute angle) θ7 relative to the extending direction of the curvedextending section 40. That is, each of the inclined grooves (the secondinclined grooves) 67A to 67E inclines relative to the longitudinal axisdirection toward a side opposite to the inclined grooves (the firstinclined grooves) 66A to 66E in the projection from the first cuttingsurface 47 side. Here, in the projection from the first cutting surface47 side, one side of the extending direction of each of the inclinedgrooves 67A to 67E matches a direction of rotating as much as the acuteangle θ7 from the proximal side toward the first width direction side.On the first abrading surface 47, each of the inclined grooves 66A to66E intersects the corresponding inclined groove (corresponding one ofthe grooves 67A to 67E), and forms a meshed structure (crosshatchstructure). In the certain example, the acute angle (the first acuteangle) θ6 and the acute angle (the second acute angle) θ7 are 45° ormore and 65° or less, and are preferably about 60°.

Each of the inclined grooves (the first inclined grooves) 66A to 66E hasa space q2 between the inclined groove and the inclined groove(corresponding two or one of the grooves 66A to 66E) that is adjacent(in a direction perpendicular to the extending direction of the inclinedgrooves 66A to 66E). Furthermore, there is stipulated the referenceinclined groove (a first reference inclined groove) 66C positioned thirddistally in the inclined grooves 66A to 66E. The second curved extendingsection 45 has an extending dimension L18 from the distal end of theultrasonic probe 8 to a distal position of the reference inclined groove66C in the extending direction of the curved extending section 40. Inthe certain example, the space q2 is 0.8 mm and the extending dimensionL18 is 2.25 mm. Furthermore, each of the inclined grooves 66A to 66E hasa depth T4 and a width φ2. Furthermore, a bottom surface of each of theinclined grooves 66A to 66E seen from a second cutting surface 48 side(one side of the width direction) is formed into a circular shape of aradius φ2/2. In the certain example, the depth T4 of each of theinclined grooves 66A to 66E is 0.35 mm and the width φ2 is 0.35 mm.

Each of the inclined grooves (the second inclined grooves) 67A to 67E issubstantially symmetric with the corresponding first inclined groove(corresponding one of the grooves 66A to 66E) about the reference planeY2 which is the central plane. Consequently, similarly to the inclinedgrooves 66A to 66E, the space q2, the extending dimension L18, the depthT4 and the width φ2 are stipulated in connection with the inclinedgrooves 67A to 67E.

Furthermore, each of the extending grooves (the first extending grooves)63A to 63E and each of the extending grooves (the second extendinggrooves) 65A to 65E match a position of an intersecting portion of thecorresponding inclined groove (corresponding one of the grooves 66A to66E) and the corresponding inclined groove (corresponding one of thegrooves 67A to 67E) in the longitudinal axis direction. For example, therespective extending grooves 63C and 65C match a position of anintersecting portion of the inclined groove (the first inclined groove)66C and the inclined groove (the second inclined groove) 67C in thelongitudinal axis direction.

In the cross section of the second curved extending section 45 which isperpendicular to the extending direction, there is formed into a curvedsurface of a corner radius R6 each of a portion between the first curvedouter surface 55 (a region of an outer surface which faces the firstintersecting direction side) and the second cutting surface 48 and aportion between the first curved outer surface 55 and the third cuttingsurface 49. Furthermore, in the cross section of the second curvedextending section 45 which is perpendicular to the extending direction,there is formed into a curved surface of a corner radius R7 each of aportion between the first cutting surface 47 and the second cuttingsurface 48 and a portion between the first cutting surface 47 and thethird cutting surface 49.

The curved surface portion of the corner radius R6 is formed along therange S1 of FIG. 3 in the longitudinal axis direction, and the curvedsurface portion of the corner radius R7 is formed along the range S2 ofFIG. 3 in the longitudinal axis direction. That is, the curved surfaceportion of the corner radius R6 and the curved surface portion of thecorner radius R7 extend from the distal end of the ultrasonic probe 8 tothe tapered section 41 in the longitudinal axis direction, and thecurved surface portion of the corner radius R6 and the curved surfaceportion of the corner radius R7 are formed in a projecting portion (anexposed portion) of the ultrasonic probe 8 from the distal end of thesheath 7. Consequently, in a part of the tapered section 41 and thecurved extending section 40, in the cross section perpendicular to theextending direction, there is formed into the curved surface of thecorner radius R6 in each of a portion between a region of an outersurface which faces the first intersecting direction side and a regionof an outer surface which faces the first width direction side and aportion between the region of the outer surface which faces the firstintersecting direction side and a region of the outer surface whichfaces the second width direction side. Further, in the part of thetapered section 41 and the curved extending section 40, in the crosssection perpendicular to the extending direction, there is formed intothe curved surface of the corner radius R7 in each of a portion betweena region of the outer surface which is directed on the secondintersecting direction side and the region of the outer surface which isdirected on the first width direction side and a portion between theregion of the outer surface which is directed on the second intersectingdirection side and the region of the outer surface which is directed onthe second width direction side.

Next, a function and an effect of the ultrasonic probe 8 of the presentembodiment will be described. FIG. 8 and FIG. 9 are views showing astate where a bone is cut in a shoulder joint 100 by use of anultrasonic treatment system 1. FIG. 8 is a view of the shoulder joint100 seen from a front side (a chest side), and FIG. 9 is a view of theshoulder joint 100 seen from a rear side (a back side). As shown in FIG.8 and FIG. 9, the shoulder joint 100 is a joint between a humerus 101and a scapula 102. The scapula 102 includes an acromion 103. Theacromion 103 is coupled with a clavicle 105. From the scapula 102, thereorigin a subscapularis muscle 106, a supraspinatus muscle 107, aninfraspinatus muscle 108 and a teres minor muscle 109. On a lower sideof the acromion 103, a rotator cuff 111 is formed as a tendon of thesubscapularis muscle 106, the supraspinatus muscle 107, theinfraspinatus muscle 108 and the teres minor muscle 109. The humerus 101extends from the rotator cuff 111. Furthermore, a cavity 113 is formedbetween a lower surface 112 of the acromion 103 and the rotator cuff111.

In the present embodiment, when cutting a hard tissue such as a bone ina narrow space of a joint cavity or the like, an ultrasonic treatmentinstrument 2 is used. For example, when performing the cutting in thecavity 113 between the acromion 103 and the rotator cuff 111, a distalportion of a rigid endoscope (an arthroscope) 115 and a distal portionof the ultrasonic probe 8 are inserted into the cavity 113 between theacromion 103 and the rotator cuff 111. Each of the rigid endoscope 115and the ultrasonic probe 8 is inserted from the outside of a human bodyinto the cavity 113 through one of an insertion area of the front side,an insertion area of a lateral side and an insertion area of the rearside. However, the insertion area of the rigid endoscope 115 isdifferent from the insertion area of the ultrasonic probe 8. In FIG. 8and FIG. 9, the rigid endoscope 115 is inserted into the cavity 113 fromthe insertion area of the front side, and the ultrasonic probe 8 isinserted into the cavity 113 through the insertion area of the lateralside. Further, in the cavity 113 under observation with the rigidendoscope 115, one of the cutting surfaces 47 to 49 of the ultrasonicprobe 8 is brought into contact with the lower surface 112 of theacromion 103. The ultrasonic vibration is transmitted to the cuttingsurfaces 47 to 49 in a state where the one of the abrading surfaces 47to 49 is in contact with the lower surface 112 of the acromion 103,whereby cutting of a bone spur (a bone) is performed in the lowersurface 112 of the acromion 103. It is to be noted that the abrading ofthe bone spur in the lower surface 112 of the acromion 103 is performedin a state where the second curved extending section 45 is immersed in aliquid (physiological saline).

FIG. 10 and FIG. 11 are views showing a state where the first cuttingsurface 47 of the second curved extending section 45 of the ultrasonicprobe 8 is in contact with the lower surface 112 of the acromion 103. InFIG. 11, the first cutting surface 47 is brought into contact with aposition different from that of FIG. 10 in the lower surface 112 of theacromion 103. Here, in the ultrasonic probe 8, the first curvedextending section 42 curves toward a first perpendicular direction siderelative to the probe main body section 31 extending along thelongitudinal axis C, and the second curved extending section 45 curvesfurther toward the first perpendicular direction side relative to thefirst curved extending section 42. Further, in the second curvedextending section 45, an acute angle relative to the longitudinal axisdirection increases toward the distal side, and in the second curvedextending section 45 and the second curved outer surface 56, the firstcutting surface 47 is disposed. Consequently, in the present embodiment,in the projection from each of the first width direction and the secondwidth direction, the first cutting surface 47 is formed into thecircular shape in which the center (O1) is positioned on the firstintersecting direction side with respect to the curved extending section40. The cavity 113 between the acromion 103 and the rotator cuff 111 isnarrow, and the lower surface 112 of the acromion 103 is formed into acurved surface. The first curved extending section 42 and the secondcurved extending section 45 are formed as described above, so that thefirst cutting surface 47 can appropriately be brought into contact withthe lower surface 112 of the acromion 103 which is formed into thecurved surface.

For example, in FIG. 10 and FIG. 11, the positions which come in contactwith the first cutting surface 47 are different from each other in thelower surface 112 of the acromion 103, and hence a contact angle of thefirst abrading surface 47 with the lower surface 112 of the acromion 103varies. In the present embodiment, the first curved extending section 42and the second curved extending section 45 are formed as describedabove, and hence even when the contact angle of the first cuttingsurface 47 with the lower surface 112 of the acromion 103 changes, it ispossible to appropriately bring the first cutting surface 47 intocontact with the lower surface 112 of the acromion 103. For example, ineach of FIG. 10 and FIG. 11, the first cutting surface 47 appropriatelycomes in contact with the lower surface 112 of the acromion 103. Thatis, at any position of the lower surface 112 of the acromion 103 (i.e.,even when the contact angle of the first cutting surface 47 with thelower surface 112 of the acromion 103 is any angle), the first cuttingsurface 47 can appropriately be brought into contact with the lowersurface 112 of the acromion 103.

Furthermore, in the present embodiment, the first cutting surface 47 isprovided on the second curved outer surface 56 of the curved extendingsection 40, and on the second curved outer surface 56 (a region of anouter peripheral surface of the curved extending section 40 which facesthe second intersecting direction side), the acute angle θ4 of thetangent line at the distal end relative to the longitudinal axisdirection is 10° or more and 30° or less (preferably 20° or more and 25°or less). By setting the acute angle θ4 to be 10° or more and 30° orless (especially 20° or more and 25° or less), the first cutting surface47 has a shape corresponding to the lower surface 112 of the acromion103, and at any position of the lower surface 112 of the acromion 103,the first cutting surface 47 can further easily and appropriately bebrought into contact with the lower surface 112 of the acromion 103.

Furthermore, in the first cutting surface 47, each of the inclinedgrooves (the first inclined grooves) 66A to 66E intersects thecorresponding second inclined groove (corresponding one of the grooves67A to 67E), and the crosshatch structure is formed. The crosshatchstructure is formed on the first cutting surface 47, and hence bylongitudinally vibrating the second curved extending section 45 by theultrasonic vibration in a state where the first cutting surface 47 is incontact with the bone, the bone (the bone spur) is appropriately cut.That is, it is possible to appropriately cut the hard bone. Furthermore,in the present embodiment, the acute angle θ6 of each of the inclinedgrooves (the first inclined grooves) 66A to 66E relative to theextending direction of the ultrasonic probe 8 (i.e., a vibratingdirection by the longitudinal vibration) and the acute angle θ7 of eachof the inclined grooves (the second inclined grooves) 67A to 67Erelative to the extending direction of the ultrasonic probe 8 (i.e., thevibrating direction by the longitudinal vibration) are 45° or more and650 or less. Thus, each of the acute angles θ6 and θ7 is in theabove-mentioned range, so that cutting properties of the bone improve ina case where the lower surface 112 of the acromion 103 is cut with thefirst cutting surface 47 by use of the ultrasonic vibration.

As described above, in the present embodiment, also in a joint cavitysuch as a cavity 113 between an acromion 103 and a rotator cuff 111,i.e., a narrow space, a first cutting surface 47 is easy to come incontact with a hard tissue, and the hard tissue is appropriately cutwith the first cutting surface 47. That is, also in the narrow space, itis possible to acquire an accessibility to the hard tissue and cuttingproperties of the hard tissue.

In the present embodiment, the bone may be cut by bringing the secondcutting surface 48 or the third cutting surface 49 into contact with thelower surface 112 of the acromion 103. Furthermore, in a case where thefirst cutting surface 47 is brought into contact with the lower surface112 of the acromion 103 to cut the bone (the bone spur), the bone is cutby the second cutting surface 48 and the third cutting surface 49 in thevicinity of an area to be cut by the first cutting surface 47. Thus, thebone is cut by the cutting surface 48 or 49, thereby preventing only thearea cut by the first cutting surface 47 from being concaved andpreventing a stepped area from being formed on the lower surface 112 ofthe acromion 103.

Furthermore, the extending grooves 63A to 63E of the second cuttingsurface 48 and the extending grooves 65A to 65E of the third cuttingsurface 49 extend substantially perpendicularly (along the thicknessdirection of the curved extending section 40) to the extending directionof the ultrasonic probe 8 (i.e., the vibrating direction by thelongitudinal vibration). The extending grooves (the first extendinggrooves) 63A to 63E extend substantially perpendicularly to thevibrating direction by the longitudinal vibration, and hence the cuttingproperties of the bone improve in a case where the bone is cut with thesecond cutting surface 48 by use of the ultrasonic vibration. Similarly,the extending grooves (the second extending grooves) 65A to 65E extendsubstantially perpendicularly to the vibrating direction by thelongitudinal vibration, and hence the cutting properties of the boneimprove in a case where the bone is cut with the third cutting surface49 by use of the ultrasonic vibration.

Furthermore, each of the extending grooves (the first extending grooves)63A to 63E and each of the extending grooves (the second extendinggrooves) 65A to 65E match in a position of an intersecting portion ofthe corresponding inclined groove (corresponding one of the grooves 66Ato 66E) and the corresponding inclined groove (corresponding one of thegrooves 67A to 67E) in the longitudinal axis direction. The extendinggrooves 63A to 63E and 65A to 65E and the inclined grooves 66A to 66Eand 67A to 67E are arranged as described above, so that when the bone iscut with the cutting surfaces 47 to 49, the bone is evenly and uniformlycut and the cutting properties further improve.

Furthermore, in the present embodiment, the distal end of the firstnarrowed outer surface 51 (the first narrowing end position E10) ispositioned on the proximal side with respect to the distal end of thesecond narrowed outer surface 52 (the second narrowing end positionE11), and the extending dimension L19 of the first axis parallel outersurface 61 is larger than the extending dimension L20 of the second axisparallel outer surface 62. Consequently, in a case where the firstcutting surface 47 moves to a position to be contactable with the lowersurface 112 of the acromion 103, the region of the outer surface whichfaces the first intersecting direction side (the back-surface-sideregion) in the curved extending section 40, the tapered section 41 andthe relay extending section 43 is hard to come in contact with abiological tissue or the like other than a treated target (the lowersurface of the acromion 103). Therefore, the first cutting surface 47 iseasily movable to the position at which the surface can come in contactwith the lower surface 112 of the acromion 103.

FIG. 12 shows the amplitude V of the longitudinal vibration and stress σdue to the ultrasonic vibration, between the second distal vibrationantinode A3 and the most distal vibration antinode A2 in a state wherethe vibrating body unit 20 longitudinally vibrates in the establishedfrequency range. In FIG. 12, an abscissa shows a position in alongitudinal axis direction and an ordinate shows the amplitude V andthe stress σ. Furthermore, in FIG. 12, a solid line shows change of theamplitude V of the longitudinal vibration and a one-dot chain line showschange of the stress σ.

As shown in FIG. 12, in the state where the vibrating body unit 20longitudinally vibrates in the established frequency range, the taperedsection 41 is positioned on the distal side with respect to the mostdistal side vibration node N3, and an amplitude V of the longitudinalvibration is enlarged in the tapered section 41. For example, thelongitudinal vibration in which the amplitude at the vibration antinodeis 80 μm is enlarged to the longitudinal vibration in which theamplitude at the vibration antinode is 140 μm or more and 150 μm or lessby the tapered section 41. Furthermore, stress σ due to the ultrasonicvibration increases at the vibration node and in a portion in which asectional area perpendicular to a transmitting direction of theultrasonic vibration decreases, and the stress becomes zero at thevibration antinode. Therefore, as shown in FIG. 12, the stressσincreases between the vibration node N3 and the distal end (E13) of thetapered section 41.

Here, in the present embodiment, the dimension of the tapered section 41from the proximal end (E9) to the distal end (E13) in the longitudinalaxis direction is larger than the ⅛ wavelength (λ/8) in the state wherethe vibrating body unit 20 longitudinally vibrates in the establishedfrequency range. Further, in the tapered section 41, the first narrowingdimension L12 between the proximal end (E9) and the first narrowing endposition E10 in the longitudinal axis direction is also larger than the⅛ wavelength in the state where the vibrating body unit 20longitudinally vibrates in the established frequency range. Thedimension of the tapered section 41 from the proximal end (E9) to thedistal end (E13) in the longitudinal axis direction increases, so thatthe stress a due to the ultrasonic vibration is kept to be substantiallyconstant along the total length between the vibration node N3 and thedistal end (E13) of the tapered section 41. That is, between thevibration node N3 and the distal end (E13) of the tapered section 41,the stress is effectively prevented from locally increasing (i.e.,generation of a peak is prevented). For example, in the certain example,even when the longitudinal vibration in which the amplitude at thevibration antinode increases (e.g., 80 μm) is transmitted to theproximal end (E9) of the tapered section 41, the stress σ is kept to besubstantially uniform at about 300 MPa between the vibration node N3 andthe distal end (E13) of the tapered section 41 in the state where thevibrating body unit 20 longitudinally vibrates in the establishedfrequency range (e.g., 46 kHz or more and 48 kHz or less). That is, inthe present embodiment, the stress is prevented from locally increasingto about 700 MPa (e.g., at the distal end (E13) of the tapered section41) between the vibration node N3 and the distal end (E13) of thetapered section 41. The stress σ is prevented from locally increasing,and hence breakage of the ultrasonic probe 8 due to the ultrasonicvibration can effectively be prevented.

Furthermore, in the present embodiment, the cross section gravity centerin the cross section perpendicular to the longitudinal axis C shiftsfrom the longitudinal axis C toward the second intersecting directionside in the tapered section 41 and the relay extending section 43.Especially, between the first narrowing end position E10 and the firstcurve start position (the curve proximal end) E14, there increases theshift of the cross section gravity center relative to the longitudinalaxis C on the second intersecting direction side. Consequently, in thepresent embodiment, shift of the center of gravity onto the firstintersecting direction side which is caused by the curve of the curvedextending section 40 relative to the longitudinal axis direction iscanceled by the shift of the center of gravity onto the secondintersecting direction side which is caused by the tapered section 41and the relay extending section 43. Consequently, in the state where theultrasonic vibration of the ultrasonic probe 8 is transmitted toward thedistal side, it is possible to decrease generation of irregularvibration (transverse vibration or torsional vibration) except thelongitudinal vibration.

In the present embodiment, in the projection from the first widthdirection (one side of the width direction), the portion between thefirst curved outer surface 55 and the distal surface 46 is formed intothe curved surface of the corner radius R3. Furthermore, in theprojection from the first width direction, the portion between thesecond curved outer surface 56 and the distal surface 46 is formed intothe curved surface of the corner radius R4. Further, in the projectionfrom the second intersecting direction (one side of the intersectingdirection), each of the portion between the third curved outer surface57 and the distal surface 46 and the portion between the fourth curvedouter surface 58 and the distal surface 46 is formed into the curvedsurface of the corner radius R5. Consequently, on the distal surface 46of the ultrasonic probe 8, there decreases a ratio of the surface (theouter surface) perpendicular to the extending direction of theultrasonic probe 8 (i.e., the vibrating direction of the longitudinalvibration). The ratio of the surface perpendicular to the vibratingdirection of the longitudinal vibration decreases, so that even when theultrasonic probe 8 longitudinally vibrates in the state where the secondcurved extending section 45 is immersed into the liquid (physiologicalsaline), generation of cavitation in the vicinity of the distal surface46 is decreased. Due to the decrease of the generation of thecavitation, visibility of an operator in a treatment improves.

Furthermore, in the projecting portion (the exposed portion) of theultrasonic probe 8 from the distal end of the sheath 7, in the crosssection perpendicular to the extending direction, there is formed intothe curved surface of the corner radius R6 in each of the portionbetween the region of the outer surface which faces the firstintersecting direction side and the region of the outer surface whichfaces the first width direction side and the portion between the regionof the outer surface which faces the first intersecting direction sideand the region of the outer surface which faces the second widthdirection side. Further, in the projecting portion (the exposed portion)of the ultrasonic probe 8 from the distal end of the sheath 7, in thecross section perpendicular to the extending direction, there is formedinto the curved surface of the corner radius R7 in each of the portionbetween the region of the outer surface which faces the secondintersecting direction side and the region of the outer surface whichfaces the first width direction side and the portion between the regionof the outer surface which faces the second intersecting direction sideand the region of the outer surface which faces the second widthdirection side. Consequently, on the outer peripheral surface of thetapered section 41, the relay extending section 43 and the curveextending section 40, any edges are not formed. Therefore, even when theprojecting portion (the exposed portion) of the ultrasonic probe 8 fromthe distal end of the sheath 7 comes in contact with the biologicaltissue or the like other than the treated target, it is possible toeffectively prevent damages on the biological tissue.

(Modification)

Additionally, according to a certain modification, on a second cuttingsurface 48, extending grooves (first extending grooves) 63A to 63E mayextend in a state of being perpendicular to a circular first cuttingsurface 47, and on a third cutting surface 49, extending grooves (secondextending grooves) 65A to 65E may extend in a state of beingperpendicular to the circular first cutting surface 47. In thismodification, when cutting a bone with the second cutting surface 48 orthe third cutting surface 49, it is possible to improve cuttingproperties of the bone.

Furthermore, according to another modification, a first curve startposition E14 of a first curved outer surface 55 may be positioned on adistal side with respect to a second curve start position E15 of asecond curved outer surface 56. In this modification, when a firstcutting surface 47 moves to a position to be contactable with a lowersurface 112 of an acromion 103, in a curved extending section 40 and atapered section 41, a region of the outer surface which is directed on afirst intersecting direction side is harder to come in contact with abiological tissue or the like other than a treated target (the lowersurface of the acromion 103). Therefore, the first cutting surface 47 isfurther easily movable to the position to be contactable with the lowersurface 112 of the acromion 103.

In the above-mentioned embodiments or the like, the ultrasonic probe (8)includes the probe main body section (31) which is extended along alongitudinal axis (C), and which is configured to transmit theultrasonic vibration from a proximal side toward a distal side, and acurved extending section (40) which is provided on the distal side withrespect to the probe main body section (31), and which is extended in astate of curving relative to the probe main body section toward a firstintersecting direction side in a case where a certain directionintersecting the longitudinal axis (C) is defined as the firstintersecting direction (P1). The curved extending section (40) includesa first curved outer surface (55) which faces the first intersectingdirection side, a second curved outer surface (57) which faces a secondintersecting direction (P2) side in a case where an opposite directionof the first intersecting direction (P1) is defined as the secondintersecting direction (P2), a third curved outer surface (57) whichfaces a first width direction (B1) side in a case where two directionswhich intersect the longitudinal axis (C) and are perpendicular to thefirst intersecting direction (P1) and the second intersecting direction(P2) are defined as a first width direction (B1) and a second widthdirection (B2), and a fourth curved outer surface (58) which faces asecond width direction (B2) side. The first cutting surface (47) formedon the second curved outer surface (56) is different from a secondcutting surface (48) formed on the third curved outer surface (57) and athird cutting surface (49) formed on the fourth curved outer surface(58) in extending pattern of the grooves.

Additional advantages and modifications will readily occur to thoseskilled in the art. Therefore, the invention in its broader aspects isnot limited to the specific details and representative embodiments shownand described herein. Accordingly, various modifications may be madewithout departing from the spirit or scope of the general inventiveconcept as defined by the appended claims and their equivalents.

What is claimed is:
 1. An ultrasonic probe used in a joint, theultrasonic probe being configured to transmit an ultrasonic vibration soas to treat a treated target in a joint cavity by use of the ultrasonicvibration, the ultrasonic probe comprising: a probe main body sectionwhich extends along a straight longitudinal axis of the probe, and whichis configured to transmit the ultrasonic vibration from a proximal sideof the probe toward a distal side of the probe; a curved extendingsection which is provided on the distal side of the probe main bodysection, and which extends by curving relative to the longitudinal axistoward one side of the probe in a thickness direction thereof, thethickness direction being transverse to the longitudinal axis, thecurved extending section including: a first curved outer surface facinga side of the probe toward which the curved extending section curvesrelative to the longitudinal axis in the thickness direction; a secondcurved outer surface facing a side of the probe opposite to the firstcurved outer surface in the thickness direction; a third curved outersurface facing one side of the probe in a width direction transverse tothe longitudinal axis and transverse to the thickness direction; afourth curved outer surface facing a side of the probe opposite to thethird curved outer surface in the width direction; a first cuttingsurface which forms grooves on the second curved outer surface, andwhich is configured to cut the treated target; a second cutting surfacewhich forms grooves on the third curved outer surface, and which isconfigured to cut the treated target, an extending pattern of thegrooves in the second cutting surface being different from an extendingpattern of the grooves in the first cutting surface; and a third cuttingsurface which forms grooves on the fourth curved outer surface, andwhich is configured to cut the treated target, the extending pattern ofthe grooves in the third cutting surface being different from theextending pattern of the grooves in the first cutting surface; a firstnarrowed outer surface facing the side toward which the curved extendingsection curves relative to the longitudinal axis in the thicknessdirection, the first narrowed outer surface being provided between theprobe main body section and the first curved outer surface in alongitudinal axis direction, which is a direction along the longitudinalaxis, a distance from the longitudinal axis to the first narrowed outersurface decreasing from the proximal side thereof toward the distal sidethereof; a second narrowed outer surface facing a side of the probeopposite to the first narrowed outer surface in the thickness direction,the second narrowed outer surface being provided between the probe mainbody section and the second curved outer surface in the longitudinalaxis direction, a distance from the longitudinal axis to the secondnarrowed outer surface decreasing from the proximal side thereof towardthe distal side thereof; a first axis parallel outer surface facing theside of the probe toward which the curved extending section curvesrelative to the longitudinal axis in the thickness direction, the firstaxis parallel outer surface being continuous between the first narrowedouter surface and the first curved outer surface in the longitudinalaxis direction, the first axis parallel outer surface extending parallelwith the longitudinal axis, a distance from the longitudinal axis to thefirst axis parallel outer surface being constant in a region between aproximal end of the first axis parallel outer surface and a distal endof the first axis parallel outer surface in the longitudinal axisdirection; and a second axis parallel outer surface facing a side of theprobe opposite to the first axis parallel outer surface in the thicknessdirection, the second axis parallel outer surface being continuousbetween the second narrowed outer surface and the second curved outersurface in the longitudinal axis direction, the second axis parallelouter surface extending parallel with the longitudinal axis, a distancefrom the longitudinal axis to the second axis parallel outer surfacebeing constant in a region between a proximal end of the second axisparallel outer surface and a distal end of the second axis parallelouter surface in the longitudinal axis direction.
 2. The ultrasonicprobe of claim 1, wherein the first cutting surface includes firstinclined grooves which incline relative to the longitudinal axisdirection in projection from a first cutting surface side, and secondinclined grooves which incline toward a side opposite to the firstinclined grooves relative to the longitudinal axis direction in theprojection from the first cutting surface side and which intersect thefirst inclined grooves so as to form a crosshatch structure, the secondcutting surface includes first extending grooves extended along thethickness direction, and the third cutting surface includes secondextending grooves extended along the thickness direction.
 3. Theultrasonic probe of claim 2, wherein the first extending groove and thesecond extending groove match in a position of an intersecting portionof the first inclined groove and the second inclined groove in thelongitudinal axis direction.
 4. The ultrasonic probe of claim 2, whereinthe first inclined grooves incline at an acute angle in a range between45° and 65° relative to the longitudinal axis direction in theprojection from the first cutting surface side, and the second inclinedgrooves incline at an acute angle in a range between 45° and 65°relative to the longitudinal axis direction toward a side opposite tothe first inclined grooves in the projection from the first cuttingsurface side.
 5. The ultrasonic probe of claim 1, wherein an acute angleof a tangent line at a distal end of the second curved outer surfacerelative to a longitudinal axis direction is an acute angle in a rangebetween 20° and 25°.
 6. The ultrasonic probe of claim 1, wherein thecurved extending section includes: a first curved extending sectionextending from a proximal end of the curved extending section toward adistal side of the first curved extending section; and a second curvedextending section which is continuous with the distal side of the firstcurved extending section, an acute angle relative to the longitudinalaxis direction in the second curved extending section increasing towardthe distal side.
 7. The ultrasonic probe of claim 6, wherein the firstcutting surface, the second cutting surface and the third cuttingsurface are provided in the second curved extending section.
 8. Theultrasonic probe of claim 1, wherein in projection from each of bothsides of the width direction, the first cutting surface is formed into acircular shape, a center of the circular shape being positioned on theside of the probe toward which the curved extending section curvesrelative to the longitudinal axis with respect to the curved extendingsection in the thickness direction.
 9. The ultrasonic probe of claim 8,wherein the second cutting surface includes first extending grooveswhich are perpendicular to the circular first cutting surface in theprojection from a second cutting surface side of the probe, and thethird cutting surface includes second extending grooves which areperpendicular to the circular first cutting surface in the projectionfrom a third cutting surface side of the probe.
 10. The ultrasonic probeof claim 1, wherein in a range in which the first cutting surfaceextends, a dimension between the first cutting surface and the firstcurved outer surface in the thickness direction is smaller than adimension between the third curved outer surface and the fourth curvedouter surface in the width direction.
 11. The ultrasonic probe of claim1, wherein a first curve start position at which the first curved outersurface starts curving relative to the longitudinal axis is positionedon the distal side of a second curve start position at which the secondcurved outer surface starts curving relative to the longitudinal axis.12. The ultrasonic probe of claim 1, wherein the probe main body sectionand the curved extending section are configured to vibrate in anestablished frequency range in a state where the ultrasonic vibration istransmitted from the probe main body section to the curved extendingsection, and in a state where the probe main body section and the curvedextending section vibrate in the established frequency range, a mostdistal vibration node positioned most distally among vibration nodes ispositioned on the proximal side with respect to a proximal end of thecurved extending section.
 13. The ultrasonic probe of claim 12, furthercomprising: a tapered section which is provided between the probe mainbody section and the curved extending section in the longitudinal axisdirection, and in which a sectional area perpendicular to thelongitudinal axis decreases from the proximal side toward the distalside, the tapered section being configured to vibrate together with theprobe main body section and the curved extending section in theestablished frequency range in the state where the ultrasonic vibrationis transmitted from the probe main body section to curved extendingsection, wherein in the state where the probe main body section, thecurved extending section and the tapered section vibrate in theestablished frequency range, the most distal vibration node ispositioned on the proximal side with respect to a proximal end of thetapered section, and a ⅛ wavelength of the vibration is smaller than ataper dimension from the proximal end of the tapered section to a distalend of the tapered section in the longitudinal axis direction.
 14. Theultrasonic probe of claim 1, wherein a first extending dimension of thefirst axis parallel outer surface in the longitudinal axis direction islarger than a second extending dimension of the second axis parallelouter surface in the longitudinal axis direction.
 15. The ultrasonicprobe of claim 1, wherein a first narrowing angle of the first narrowedouter surface relative to the longitudinal axis direction is larger thana second narrowing angle of the second narrowed outer surface relativeto the longitudinal axis direction.
 16. The ultrasonic probe of claim 1,wherein a distal end of the first narrowed outer surface is positionedon the proximal side of a distal end of the second narrowed outersurface.
 17. An ultrasonic probe used in a joint, the ultrasonic probebeing configured to transmit an ultrasonic vibration so as to treat atreated target in a joint cavity by use of the ultrasonic vibration, theultrasonic probe comprising: a probe main body section which extendsalong a straight longitudinal axis of the probe, and which is configuredto transmit the ultrasonic vibration from a proximal side of the probetoward a distal side of the probe; a curved extending section which isprovided on the distal side of the probe main body section, and whichextends by curving relative to the longitudinal axis toward one side ofthe probe in a thickness direction thereof, the thickness directionbeing transverse to the longitudinal axis, the curved extending sectionincluding: a first curved outer surface facing a side of the probetoward which the curved extending section curves relative to thelongitudinal axis in the thickness direction, a second curved outersurface facing a side of the probe opposite to the first curved outersurface in the thickness direction, a third curved outer surface facingone side of the probe in a width direction transverse to thelongitudinal axis and transverse to the thickness direction, a fourthcurved outer surface facing a side of the probe opposite to the thirdcurved outer surface in the width direction, a first cutting surfacewhich forms grooves on the second curved outer surface, and which isconfigured to cut the treated target, a second cutting surface whichforms grooves on the third curved outer surface, and which is configuredto cut the treated target, an extending pattern of the grooves of thesecond cutting surface being different from an extending pattern of thegrooves of the first cutting surface, and a third cutting surface whichforms grooves on the fourth curved outer surface, and which isconfigured to cut the treated target, an extending pattern of thegrooves of the third cutting surface being different from an extendingpattern of the grooves of the first cutting surface; a first narrowedouter surface facing the side toward which the curved extending sectioncurves relative to the longitudinal axis in the thickness direction, thefirst narrowed outer surface being provided between the probe main bodysection and the first curved outer surface in a longitudinal axisdirection, which is a direction along the longitudinal axis, a distancefrom the longitudinal axis to the first narrowed outer surfacedecreasing from the proximal side thereof toward the distal sidethereof; a second narrowed outer surface facing a side of the probeopposite to the first narrowed outer surface in the thickness direction,the second narrowed outer surface being provided between the probe mainbody section and the second curved outer surface in the longitudinalaxis direction, a distance from the longitudinal axis to the secondnarrowed outer surface decreasing from the proximal side thereof towardthe distal side thereof; a third narrowed outer surface facing a side ofthe probe toward which the third curved outer surface faces in the widthdirection, the third narrowed outer surface being provided between theprobe main body section and the third curved outer surface in thelongitudinal axis direction, a distance from the longitudinal axis tothe third narrowed outer surface decreasing from the proximal sidethereof toward the distal side thereof; and a fourth narrowed outersurface facing a side of the probe opposite to the third narrowed outersurface in the width direction, the fourth narrowed outer surface beingprovided between the probe main body section and the fourth curved outersurface in the longitudinal axis direction, a distance from thelongitudinal axis to the fourth narrowed outer surface decreasing fromthe proximal side thereof toward the distal side thereof.